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PCM Programing/Tuning-Lets make this even better and easier

12K views 69 replies 19 participants last post by  AstroWill 
#1 ·
So there might be a few people that need or want to have some changes done to their PCMs and it may not be worth it to invest in the hardware/software to do minor changes and such.

So I'm going to start doing this for the 96 and up PCMs, for now I am going to offer up the ability for you to make the following changes:
Modify EGR/AIR/EVAP/VATS settings
Change VIN number
Adjust for different sized injectors(for marine or 2114 intake swap).
Adjust for tire size/gear ratio changes.
Enable electric fan control on models that support it(97 and up?)

Eventually, this list will expand, to include tuning adjustments, depending on what you guys want/need to have done.

UPDATE: Winnivan noticed that Open Source PCM programming is now available using PCM Hammer and TunerPro with the proper adapter for supported PCMs. Note that most of the PCM/OS from our vans are not supported. But for those that are, it's a great option.
I recommend the VXDiag VCX Nano available for about $100 for the USB version, and $120 for the WIFI version https://amzn.to/3cFPw53 would provide good versatility as it comes with the Tech2Win emulator that can do virtually everything that the Tech2 can do. Make sure to shop around as prices can vary.
Or you can use a cheaper ~$60 OBD2 Bluetooth Adapter https://amzn.to/3xhmyjH
GitHub - LegacyNsfw/PcmHacks: PCM Hammer & PCM Logger, tools for General Motors Powertrain Control Modules (PCMs).
TunerPro and TunerPro RT - Professional Automobile Tuning Software

Attached is the PCM pinout spreadsheet for the 1996-2005 A/S vans PCMs If you need an office suite to use with it, I recommend https://www.libreoffice.org/ As always, remove the .txt from the file name as our forum software doesn't allow me to attach spreadsheets.
 

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#2 ·
You the new computer modification guy.
Since this is your thing. And your doing a good job I may say. The dinosaur computer info was awsome.

Do the world a favor and make a list of the protocol for making body and engine computers communicate as you run across them. It makes the 2 computers sync and sets the passkey systems without the dealer only scanners. For the poor SOB's that eventually need to put a computer in.

After talking to the dealer guy. Seems the computer if it has a dead battery more than a few days will loose this and need reset. And the computer may fry when a new battery is installed. So always keep a trickle charger on it when working on it and the battery is out. They actually recommended keeping it powered while changing the battery to avoid the power surge that damages the computer.

Hey I aint making this crap up either. I put a engine in a buick and the computer went out from not having a battery in it for 2 weeks. Put a battery in and the headlights flashed and went out. Computer was dead after that. After that one or the other headlight would periodically come on when the light switch was turned on.

It is a silly combination of random acts that clear them and make them sync to work as a unit. I sheet you not the buick had as example. And i don't remember the exact order. You turn the key on and off 3X lock and inlock the door a couple times. Then turm on and off the radio in a certain sequence. Then you get a dash light signaling it is activated. Wait till it does its little flashing lights show.

Now the key and computer for the passkey system work both computers are in sync and it starts and eveything works.

But you sill got a code it was the wrong vin. Which never got fixed.
 
#3 ·
I'd LOVE to be able to adjust my timing and make a few adjustments on my 2000! I'll be watching here with interest!

In the meantime... the only thing I can easily do is make adjustments on my 92's carbureted V8 without issue, without programming cables, without a computer, without a specific program or programming knowledge! :D

My 92 can also sit dead for ANY length of time... and with fresh battery it will fire right up every time! :D

So... what do I need to get started? (not my 92..lol)
 
#6 ·
Wimpazz said:
Will do you have a TECH2? You're welcome to use mine for the cause, PM me.
I have access to one on and off, but have decided not to buy one. I will be getting one of the $100 adapters to use with Tech2Win(does everything tech2 does but in an emulator).
 
#8 ·
#9 ·
keep us Updated on this adapter. I can't justify buying a Tech2, or any scanner that is in the 500 dollar range used that is halfway decent for my own use, this would be nice to use with my laptop ( which I paid a whopping $90 for this summer ).
 
#10 ·
redfury said:
keep us Updated on this adapter. I can't justify buying a Tech2, or any scanner that is in the 500 dollar range used that is halfway decent for my own use, this would be nice to use with my laptop ( which I paid a whopping $90 for this summer ).
If you keep an eye out on sales and such, the clone tech2 can be had for right around $200, usually $250-300 without a storage case. But the Tech2win software is faster(depending on the computer you run it on), larger screen, touchscreen support if your laptop has a touchscreen, etc etc.

I can also confirm that using the RedDevilRiver ALDL adapter(they have them in bluetooth as well, but I have the USB model) in combination with ALDLdroid and a microUSB adapter work perfectly with my tablet on the older models for getting real time information out of them. Not as easy or cheap as OBD2, but you have to work with what you have.
 
#12 ·
dramey said:
They ship worldwide but not to Alaska. idiots.
Who are you talking about?

BTW, I won't ship to Alaska either ;)
 
#14 ·
dramey said:
I was referring to that adapter in the ebay link that corsemoto posted.
Just grab one from a different seller.
 
#15 ·
chevymaher said:
So always keep a trickle charger on it when working on it and the battery is out. They actually recommended keeping it powered while changing the battery to avoid the power surge that damages the computer.
I think that is more of removing the battery to charge it, some of the crap chargers will put out more than 17-18volts and yes, that can definitely fry computers. So if you are using one of those chargers, definitely remove the battery to charge it which really is a good practice anyway.

chevymaher said:
It is a silly combination of random acts that clear them and make them sync to work as a unit. I sheet you not the buick had as example. And i don't remember the exact order. You turn the key on and off 3X lock and inlock the door a couple times. Then turm on and off the radio in a certain sequence. Then you get a dash light signaling it is activated. Wait till it does its little flashing lights show.

Now the key and computer for the passkey system work both computers are in sync and it starts and eveything works.

But you sill got a code it was the wrong vin. Which never got fixed.
Don't forget to do it during a full moon.
 
#18 ·
Mmusicman said:
I'd LOVE to be able to adjust my timing and make a few adjustments on my 2000! I'll be watching here with interest!
In the meantime... the only thing I can easily do is make adjustments on my 92's carbureted V8 without issue, without programming cables, without a computer, without a specific program or programming knowledge! :D
Just carb the 2k, problem solved. ;)
Mmusicman said:
My 92 can also sit dead for ANY length of time... and with fresh battery it will fire right up every time! :D
Your 2k should do that just the same, my 99 sat for about 3years, threw a battery in it, and it started just fine. I miss that low mileage beauty... :(
Mmusicman said:
So... what do I need to get started? (not my 92..lol)
A carb ;)

I have thought about getting a programmer that I can get a deposit, send you the programmer, you flash your computer(would only work with the VIN you supplied) and then you send it back(or possibly to the next person) and I refund your deposit. Problem is that the programmers are a LOT more expensive than what you can get a used PCM for.
I want to keep this as cheap as possible for everyone, but I would like to recoup some of what I am going to put out for it as well.

The option that I think will work best for everyone right now is to mail me your PCM, I will hook it up next to the computer, read the original calibration, email you that calibration, make the changes, reflash to your PCM and then I mail it back to you. I can even set it up so that YOU do all of the changes to your PCM through the likes of Teamviewer or something similar.

I want to keep this as cheap as possible for everyone, but I would like to recoup some of what I am going to put out for it as well. What do you guys think would be fair for such a service? Send in a donation with your PCM ;)

I would like to get a few PCMs and wiring harnesses as well, so someone that lives in the lands where you get PCMs from the JY for $20, they could ideally grab two(or more) of their PCMs for $40(and the wiring harness as well please), send them to me, I program one and send it back so you can just swap it out with no down time and I get to keep the other(s).

Thoughts, ideas, please speak up.

Corsemoto said:
Corsemoto said:
Thanks Will, I've been researching and thinking about Tech2Win as well. Is this the adapter you've been looking at or something different?

http://www.ebay.com/itm/New-VXDIAG-...:g:yZ8AAOSwoudW2k~d&item=252297917469&vxp=mtr
Thanks again Will.
Any time.

markmitch said:
anyone have the ability to do 1st gen vans? I need a chip burned eventually after I add vortec heads, headers etc for my V8 which is a 92 TBI 350
Just carb it ;) There is a slight chance that I get into these as well, but don't hold your breath.
 
#20 ·
I got a newer(411) PCM for my Astro from a guy on the GM performance forum for 99 shipped with a base tune about 3 years ago. A butt dyno tune locally would have cost me an additional 200 bucks, where a full Dyno tune would have been upwards 500.

So, your time is valuable, but we want to serve as many customers as possible, so figure out your time x the number of units you hope to see at that price point. If you invest 1500 into the software/hardware and only do 10 computers, then you are going to need 150 each to cover shipping costs, your time, and part of the cost of start up. You can always ala carte certain options if you want to...mostly depends on the logistics of the whole thing. If you do it like a group buy and you get 20 people to commit, then you can lower the cost.
 
#21 ·
There's a guy around here that has a fairly ok name at using tuning software. He helped me out once. Tuned the computer to compemsate for going with no catalytic. Did it for 100 iirc. He made me the offer of 350 for a performance tune. Had a guarantee to put it all back to stock if I didn't love it. I definitely considered it.
Just throwing that out there for info.
I'm definitely very intrigued by the idea Will, especially if i don't have to live without a ECM.
 
#22 ·
Definitely want to keep it as cheap as possible for the group. I was thinking ~$60 plus whatever the return shipping would be for all of the basic stuff.
I don't do any of this for profit, just for fun.
 
#23 ·
When it comes to electronics I am going to need the dummies guide just to locate the PCM so this is of considerable interest to me. There are some things I have planned that I know are going to affect the settings so having someone to help with the tuning will be great.
 
#24 ·
Wow, can of worms.

I don't know what all you will be able to modify, but if you let people start messing with the reference tables (which is essential for any sort of performance tune) holy shit. I cannot even imagine how many times that PCM will get shipped back and forth for reflashing.

Unless you are going to provide modified tables to upload for those dummies who don't know anything about tuning a computerized vehicle (99.999% of us), I just don't see any actual "tuning" happening. For performance tuning you will need to have pre-configured tables for say "towing," or "street racing," or "super cheap fuks economy cruisin," etc. Do you plan to offer something like this? Are you qualified to make educated changes to those tuning parameters? For the masses who have never seen them, there are about 100 tables with thousands of numbers in them that the computer references to make decisions regarding how to mix fuel and air, shift, you name it. It's extremely complex.

If you have actually been deep into these computers you know it can get crazy ugly real quick. Often needing to reflash a PCM for performance tuning several times in the driveway before the engine will be happy enough to get to the street.

I dunno man, sounds great to be offering the service but I think you're creating quite a headache for yourself.

Good luck! :rockon:
 
#25 ·


Yeah something like this. You put a period where a coma should be a boom goes cylinder number 2 or something like that.

Very difficult to do well, and very few people have the time or patience to master. In a past life when I was into tuning subarus I messed with programs like this. You can do pretty well if you tune for air fuel ratio, but without you sitting in the car and doing multiple passes to verify corrections its probably not going to end well.

The only way that becomes convenient or easy is if you have a tune already for someone and then another person comes a long that has the exact same mods. Assuming everything is the same, then they could share a tune.

Performance tuning is a can of worms like CC said, but if you just wanted to turn EGR or o2 sensor codes off that should be pretty simple. Or at least it was on the few tuning systems I have used.
 
#26 ·
Indeed, if you are tuning to the edges of performance there is no efficient way that you can do it without having the vehicle in front of you where you can change, test, change, repeat.

That is why the generic 'mail order tunes' have only very slight changes to them.

Again, that is not what I'm offering right now, it's possible that sometime in the future there might be an equivalent to a generic mail order tune.

But if you want to change the o2, egr(only for off-road use), speed or RPM limit, etc, then this will be a cheap, easy way to do it.

I will be set up to do 2003 - 2005 and 1996 - 97 in January, will add more as needed.
 
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